They’ve spent a half-year admiring it through fences, and now New Yorkers will finally get a chance to enjoy a long-delayed Brooklyn waterfront park.

Officials told The Post that they plan to unlock the gates to scenic WNYC Transmitter Park in Greenpoint on Saturday.

But neighborhood activists say that’s way late.

“The park looks great, but the city messed up,” said 50th Assembly District Committeeman Lincoln Restler. We’ve been staring through a fence for six months at a park that looks complete, and now “We’ve already lost most of this summer to use it.”

Officials insist the 1.6-acre park wasn’t ready until just days ago, pointing out that safety railings were installed along the East River shoreline only last Thursday.

But Restler’s not buying it. The opening, he noted, just happened to be announced days after The Post began inquiring about the delay.

“The city needed a real kick in the ass,” he said. “Whatever work was done the past six months could have been done in weeks.”

The city claims this is untrue.

Fueling the community’s ire is that the Bloomberg administration has yet to deliver roughly 50 acres of parkland that officials promised North Brooklyn residents in 2005 while pushing through a controversial rezoning plan which has brought thousands of high-rise apartments to Williamsburg and Greenpoint’s waterfronts.

When it opens, the project at the former WNYC radio transmissions tower site on the river’s edge between Greenpoint Avenue and Kent Street will be first of this promised green space fully delivered.

The “Parkgate” controversy began there in March when workers started putting final touches on the city Economic Development Corp.’s $12 million project.

Local pols and other community leaders thinking the park looked done said they began routinely asking city officials why it wasn’t opened but never got a straight answer.

Over the following months, local hipsters and other passersby got so restless that they started sneaking inside, witnesses say. In fact, the park was flooded with patrons one May day when workers accidentally left the gates unlocked.

“The whole neighborhood is so frustrated that people have been breaking in to enjoy it,” said Brian Crowe, who runs The End, a recording studio and performance space located next to the park.

“This park looks great, but so many people would’ve loved to have used it this summer, especially Fourth of July,” said nearby resident Adam Gacioch, 26.

Councilman Steve Levin, who represents the neighborhood, said he’s also “bothered” by the project’s delays but added “at least it’s built unlike” the 28-acre Bushwick Inlet Park project and other green space planned for North Brooklyn, which “severely lacks” parkland.Transmitter Park features an esplanade, magnificent lawns and a children’s playground with spectacular Manhattan skyline views. A recreational pier that is also part of the project won’t open for a few more months. The city also plans to convert the former transmission towers building onsite into a café with rooftop seating and public restrooms, and it is considering offering kayaking onsite.

Kyle Sklerov, a spokesman for the city’s Economic Development Corp., said the agency is “excited” about being able to “provide important new waterfront open space to the residents of Greenpoint.”